Many medical and dental professionals use head-mounted lights to better visualize procedures. However, different spot sizes and/or light intensities are preferred for different situations. For example, whereas a wide-angle spot may be suitable for lower magnification and large surgical fields, a more narrow, high-intensity beam may be desired for procedures that require the brightest light. In many instances, the spot size is matched to the magnification or field of view associated with telemicroscopic loupes worn by the same user. Currently, however, to change spot size, purchasers need to buy different head-mounted units, raising overall cost.